SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10ad47fac5705e9759f5436e45aecaedca499308ab9ea7dd7d72b689c8c3efad' 
  AND token = 'Gk1JJzxmwteKZoiCdYXtay7A36c6rsUT2Bnqn2A+Tso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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