SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8585141bca8138d0c62301b88c215bc4b25d284a4cbf93ed900780367520750' 
  AND token = 'wQZUnJ7TJmO7+MbJ1aXTaPrhA83oqBLiLZmiZxGtKvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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