SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f79797302e5d9172af048cb2dd605a3a174fe1cc8c40d776c93e21aaa3bb2ae' 
  AND token = 'P9afMcaHpCiTByK4VmavSn4QT5oooLKWiC5sMoau9kE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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