SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6d7c8fe05002ee3b5522d4852ede25d7eb6cb2f0a7575dc67c80d201d4820655' 
  AND token = 'UUBQ0WENOYyhogMy+cITrHae0qLd40THS+zrSGMwdNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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