SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d7bb487f58592cc4aacf2c57c6e3b7dc43aa8b0372053ca13ecd93a52ebf7c3' 
  AND token = '1PV3UBqaF+HP9hFaAdkGZQZSPV2S8SJzcSVOSLP3EBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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