SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f19b4844513af7ab295593e5e4cdf815324225c05afc047610cab446dbf95d9' 
  AND token = 'u3IzoprfnYZCHBFtgNR4CnVVpdOoIfTocxpQeVCyOss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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