SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09705f51822ffff8ffbcf2a3e893702ce2ae3049482a297060e463887480b1b3' 
  AND token = 'enrAJAjF0XYUjemPPkGK12+oa35Cf92KeGr70wOQpkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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