SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48e269f68ef9ffd255ebd65d33bb87cec3b484534cc7f1ecf8eaa7781f83115f' 
  AND token = 'FoPyAgT9vRup7oSsN4rJ+ysZVI4WR+YiyhL6PuSRS88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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