SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e614756feade4611ddded15fbfdc5bd271b37d7266ddca6a6030737cd9d8d815' 
  AND token = 'wlvfibmji0iEET1om9XIEjcX9/3MIFEsk+4t1LV6Trc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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