SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '459838dbb39f981d0b8fed449d10d4710925aef1ca8cb036184131cb866e6600' 
  AND token = 'mgaw4RQ3MK9y+OfuoLsxjXuSUXM7Z1bBS3Uy9Lws7gY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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