SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee631579e1a8b7a019bf977f31689f87a24b5a95e8d5fb91de9dc997d307d8dd' 
  AND token = 'Y2hJBiNyY2UzDcMFqir2Mk/KnzDJ6euCH8FiRXGRGQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}