SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a6ec34af76b0917d66420567a60cab81f38cfb91625c11d389d11a47271b91e8' 
  AND token = 'niAC7bYbtD7MIIjYp7rVZPPgd6xgL4pwz7jsLPoGGhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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