SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d52add94ef2b6a21df3430bec8962260c7d6d2ba9deb642b523a38a798be801' 
  AND token = 'hDnxZTSKeufRAXaqjKiHw77lIFBQQrMdHKWUW7h1zGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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