SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '992ea57aaa60194749d47d915669761c147f698ae5f69dfdd009a97269883ad7' 
  AND token = 'HoaArw9yjMgELnxq/3067pRudTHrsYCrikNc2BMbOVE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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