SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '543c8f6e382f385eae258e89312c4cc08f65cfb3991c3644dd65e3b7b0235afc' 
  AND token = 'in9Z9wORlKRSfzjzvmSxcT8dDyaQ8GTdFxnVoWIdHIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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