SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3154284930baf977c6c3322871df40f4b7d174961213f9ab0fed225c67434743' 
  AND token = 'xRm9g3FuxnYfAzg4xbtngQjbTIRSV7GfBDNVvAibSWk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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