SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5ca71aa5c0fbda4b702789167144574e09ec20a8bf4f92cc2c52be7917cfe6e0' 
  AND token = 'E5KXHlPylappn7O5xCYttqWYcG7q/peI383rqesJENQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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