SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc61d3d9619fecade56876f101481b86c850f58b0e84673eb88f3f3cd787bf33' 
  AND token = '/aj9yzQ7zihcsAc1Au307GdM8Mi8gTPCvTU8UcgoV30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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