SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c72c515418f792f18fbdaa94c23e8e60fa7b20c54da339b49fc7ed6ffcc297b3' 
  AND token = 'NE+eksAsnIxoysBCEwg7D9PViDpMohS2hFpPZcPYHtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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