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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f358d2cb1e14bda31c1ba47fe2ffd9a7e99385ba7bd14ac077eb6a3652b67814' 
  AND token = '9mg57ORqQEL/7a6wbrLSaTYuqwlxt3+RtpQVrIB/hkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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