SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77fb024963bc57ea3285f18343f6ca0ba31b4fdef32d1868729e38e5210b5263' 
  AND token = '4Hh/arlYrJJ6mhQ7cAJ/ozhpw9BVwFp+qOdvk7KWkDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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