SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcffc36d2de2b2bfcdc0a4f0436eb3360a412ed04ae54cc895f3940c68f99f57' 
  AND token = 'b7r70eu9drs9B+gdugiwG78dIqZBwA3KsVRQlzhM65M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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