SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c442a33f634c82d510f2b7aa6f59c20d23d592049cf7ed3ad9a57bbfe17ff2ac' 
  AND token = 'piEwhM/C+8HYIlxZKH4jZpxHcvTf3bnmDgHKuI6JzPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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