SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd28d4a600316d3cd810a7919ebafdfb87e631de608471b8a36f377c4bb9e035f' 
  AND token = 'pXVdxuBJKnQhy50TAhKfySw2UP+gOeCqyqS6DdlrU8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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