SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34046bf495a9d24d5bd941a4724b5140b31dcb489b524fdbf5a992bf650415ed' 
  AND token = '8JfCeAm8yzrI8d0q5RdAMsjvsKucGtlzmQotJClEcmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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