SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67ed4e47c2b1f750ba485e802d5884885152f383726e6dda793248b6e135d77f' 
  AND token = 'lxNwlPA7OVxiBVE+LQ8jZd0EZ12vb4AF9cwDkxaBlJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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