SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e242589fdae6b5f8565f553d7bdb763dd762acc30ac5ca77535d5375e78e84c' 
  AND token = '8YPhmedIxqzJl0TmFAyOvNm+OEY3h7EZA7dTdD+O1as=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}