SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5edc285943fbe4b24de15c087d14c3be9c888fa0a7747e229f9911810259578' 
  AND token = 'yMb+YLGPDjGoGqxyuM3STyj6AWQioFJKPvHvF6KEzIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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