SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f821a78e1764696d8162a59ec9d1aeca04229b79b8fe87911d94a862515a5749' 
  AND token = 'LAdFZDT9rS/w57FqhvYT9VPtSyjGQKxqgjBhJi9x7ZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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