SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b7ab65a4058b5902fbbd30b096e22031662abdeb9d3e4c944893acc65138a65' 
  AND token = 'kqkdEPDDUOB5LHTOlfV2tekdKctITCJZmqTon/RA/5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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