SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f989a123fc3deabfb0e847e1a934902b54bbee81ecb1d5340c15fbcf78864e29' 
  AND token = 'aEMUYihD+uMFndz1ZRV7uyBSD5Vh8R8UQXGEfhbm08k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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