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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd55cfc7eb25e9dcdad342fa977d392eb3b6db9b9b047ac99a3cda15ea4878331' 
  AND token = 'uWYNB+sj4fSdDoKE7pg2CPr1Qa7UsJ3AK0pwPuRyuQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}