SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30afd523d9d0dd756ade1dbf33095878d8bb89fa5553cef81fed740f0ec776da' 
  AND token = 'YmJCNUY8CoJ+BTOs9hxKZ5TZT6yrlZDpPq1QD4uknZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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