SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7781aee1a32b5572b818eec785807a644b3126da4f6d30e2b5becde1a2b8068a' 
  AND token = 'zk5eSMBCZXidteQqaWPR9NTbXmXi2Z8ToUylYXkht+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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