SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3160681d82d3083ef3fc0d156fee422bfd4c72a993f32f4ed4f36cabe794ab71' 
  AND token = '5lNxghmTdKltr5WFY2AFllyqj/6IBtd26zf/v5j/fvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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