SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ef4a9cc06148d0d910031993e9c0dd7c56cfa9a6daefc79a7aceaff71b2a507' 
  AND token = 'aowDoBwvLgqg0wthkwJDg2qYXlHP54omByoTMkqAfEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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