SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53797e772bf74d347818de86fdb95f2f6fda580ca572e9d801f2ada7933aed25' 
  AND token = 'Qk3fdx1mxR7yYZVlj9SQNrdZSIOASJdihz9NTc2o0S8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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