SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d7ea42feccefc4ed5c44076dd84708e0487436c6f0f08289ce8226ae8a68dad' 
  AND token = '/gMi6knZc5bX8Fy3Mg3ILaSdGBlgSRuebZlKCUegeHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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