SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cb45eabed5e598439995e53487ae2336dd5bbd48c4c5f31370b5489ef3893c9' 
  AND token = 'XkxGWqzliPv/CutSwGHQyKFpDZoVKMxkFPdRWqySsMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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