SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b5c30eb472f8f2f6eb710ac1dfc05cb87e1790f07cc174f9ea37a6e2843dd70f' 
  AND token = 'o9WdVmnF+ui0VuhOoglMpRTkzUmWRZOOY5Vvhs257VY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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