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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8712d7b5c65bc3a54e27a47f4958bb51281b694957e656da5b1ff0aa585e5b3c' 
  AND token = 'nJJ5ZySUttkiAreE6dSqp9fZ4f1AfMVyA+3Fx4hevEY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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