SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f28f49c2359c63d8124e0a21a0c5c4b0bf69bae89ea6588179ff1c2efac5a6e9' 
  AND token = 'SlARkH9t6QwcnHlzE0PVeVfXTGzHMPIWEXm8nr9RtuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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