SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa2987ed59eedbec7cc3f273913077c63eeb2a9b50bbf1d62074687d7da04ebe' 
  AND token = '9/I7NW7cAUcdsWBFl8KlSAye8ZqgCuktfUgWwQO9jDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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