SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84abdf15f207eb8500d74c20625fc879e802c6f639f608be7923de29b40e67f4' 
  AND token = 'c2pAjXTVOE1tnGHjkJeJRhnbFlXATRGvyao5OmAKNkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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