SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '337b4dbdeb359d2e257c3dc59bf7df0e914408fd022cd37499e979a4c0f72981' 
  AND token = 'xovAT5K/6eUb8pWo3QdqOdhmCgroym597AqXLHjEtEs=' 
  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"
    }
  }
}