SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea4bd007da1a0756402bc075c6667aa1db338cee8ef9634038975b53f42f067e' 
  AND token = 'sYuj87kR4L5GUwZ8xp05C0iB68iDIJXR01UXCzlsydU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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