SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88d8c34a67baf92688b8b65193305659d8573326fd0cbf51a9db10c7cbdd7ffa' 
  AND token = 'yJyxNAb5fj+5yPErsww4MucRkTeXPyYcQYX8+P7ElyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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