SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b9f4bf28005c69a8384ba7d88e1d3116409e377a5aa9639fe1e12efbf2c7df42' 
  AND token = 'XczPFA5AJNdhRJD6A64TQfH9W8CZgO0U+1Uxc55umGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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