SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfef35c19e64986bf0fa95a33f9c7352f986c8ea1edab17a3449b9d158da5f2d' 
  AND token = '1fXFUTN7X2CN6anKoJeLIwiSENA/aJgfZvgXyTpIIew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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