SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55f2547dd556b486ce8ba15b5f206d071b81f3aac188f5b41acd519fc6d49cc6' 
  AND token = 'mNjlG8HfmQaz2BFz6w+cNVvRxH++6TqA/LKVgsqdKwY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00066

JSON explain

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