SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6788b2cef85d54bc689803c7fdd9bd05935753d0191dc4230c715264a1d6494' 
  AND token = 'lj0TS6cMJkHxCm0ujCCVNq8QaffZcmgdbsJvtRMsJbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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