SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b209706728d876588c12cd828fb87316bb140acf4b9d20956098ebb66b04d3b4' 
  AND token = 'cxD2oXD/U6LGHE1mjOqX6IKAQiy8ATkZ9AffRPr7Gyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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