SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f438c71348f0337fe3cc120fece3320c6c70ddc368c63f7703f5e50a7593f5e2' 
  AND token = 'dpuZpCir0wDW2NtCt4v3RByRLNHUOGHysc7LISfcEm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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