SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02728e29534a6d3c69b832be1fdac6d942294dacbe2d06632fa8b32a5da71ed5' 
  AND token = 'rcbistXVasHWXCTW8Oa89CIVnaPhiOWGIwIiTNB9uuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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