SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2d083aef7f04a557ae22ed1adbc3c8560215a374ca72cdc1274fd7f0ee2bcf8' 
  AND token = 'fPo48vQW3AANZ/OZWt3XsVZOMFl+Had0BPRwTqLOQrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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