SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27d68a7b74778fd679f3aedb3dc3f005c0127a57459743820adcb0e643974e76' 
  AND token = 'fm2ukb7ASesXjGt/+lBzDjKdIa+o4bPulcNKosOE+t4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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