SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d7e62240a511da725fbb12b0da8f6d6200a3a948d51c083c88258699632c970' 
  AND token = 'gCt9lOaqNPc6FD28ax/BcUxJMCLgVSRIEjhvSqZtDN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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