SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ec299989e5f4ec2b92c69ad6d1252a1932081393024687b67253c0028920871' 
  AND token = 'ag9c19KeskKqYE04GV4zPf/WCRL79nY3SDCxX4MDrB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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