SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7a855b35936af5736ce2eff4224906e346cd012a424239681d69f76d8e46bab8' 
  AND token = 'Yu90JsrsJZ3jf4KBNwmjQ5AewDVH/CGxvoeK+TklFjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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