SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4da5732f75cd55d4e230813ef1d919894537adaf2a084eb1dbb635cd50f22146' 
  AND token = 'OxCx1PB0OjzY4MOwIN3GndEmCZn3CktvECsICf0nHuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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