SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9afe01b407133bb91289de41af791c674997c8840d1456656e77b8962c5194b3' 
  AND token = 'TlCeqwPBreLNGA+BjgasU1rbRxeDK+9fY8QmjzhKD7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}