SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a8ad81515a9b5c3a7b4475fdb5d1e26b4fdf255f6fa61d7c6c1750eb6387096' 
  AND token = 'GshfrGGoJUhuzDK1znFLLbr4rI1Fctv2g+XHagjuP6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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