SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4a9586b2a832df6acdb31d2b59e262794be61487eaeebf70a0a62b86935b9414' 
  AND token = '7k4kzXdBJv3wXl6ctjWYMYscun+OVihNcQs9C5qN3Cs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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