SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1f8d4e61091decd6967e463c78ae31cab45cb554cc2d75a196a5e106f6f2f72' 
  AND token = '1Hl0QtaKrTsZDMhW6AUouyS+txa6wknQVcBW80q+Rwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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