SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a347f2a14941635b905b5c3ba55c575a5ba7d9791bba96bc9e8b09282e2b0aff' 
  AND token = 'qWps0A6bU/vYSvjVwco7FYeRWbW+lv0pImuZ6ggmuIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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