SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'eb46723de1eb2722219f17841767520d5bc6392c2df052b5d49156bbd9e1c9ce' 
  AND token = 'Dxas7ub/EpznjzrrQOWnm6NnJkuWPt+ha6B0mE0XlQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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