SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e379ed84859c05c6cf258b96aaaa7aa60d54d41edeb4c3d33fc7beb6a90e7a52' 
  AND token = 'iIB7XLocvJGJTVg5ogKK07+dQlbiKJbuQOL9GEt+Mek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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