SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3aa66f9fc2f1b9cf23ddb706c2db15e4ff975497ec755671a408e4c84dd86fca' 
  AND token = 'qlsdebNc6s8ZyAQFyY2mTlTqET5yzm0apYsko/Gmvs8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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