SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6cfa6d03a152894ec3d98dfa892ed21587a31df6325bd31bdf918ac8f5bcc36' 
  AND token = 'bhU03ulKwfUKid3qVFKcd0bT1fYA2Gd3BTTNTbuaeJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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