SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f1defd3fbab552137a161f4f4adbf5c301c869343ffc847f90f9a1e08b50e84' 
  AND token = 'iiRyhuHkxlL8/YxAjhJTBG+IKLtGPzjrKsswPtsNuGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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