SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0ed7f32ae120ee985c63a1a4f0e14dde04685fd1477902ab33fd2b3254d0131' 
  AND token = '3fdWz3wZrjvMZGljTqlFR1QsZ/yTCRGcJOdz+58/ASQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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