SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b70cec9495774ef9cdf48512ad7c8cac69214c5aebd98c6f254bd202a9ca2b44' 
  AND token = 'ZGDyo0KQ3izH7r+WZfjJ1cdsgD2hEw7wvCsRUKj8ATE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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