SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff4b799e722a4044733a34b68909ac895b3cff7d60b51df8df3adda0d91eaacd' 
  AND token = 'R+ZXNSM7QSUfj6qsUS/sae7fwkIrDpHPdLXRljL6lKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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