SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '406c8bb845096bd60c4e4fb2fd8558bac76e4a21149f5237767e0e2332c73f2c' 
  AND token = '1QrcUPCK7Jal/qKsLgdg8JFlbCZ1vsO7yjqZB5Sruzc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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