SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db8c5badc4e9366df79778c66b540b54d3a7ae606e4819e6f7208db8bbd7673d' 
  AND token = 'opuQwMSR8rZFKWqM/UUtuBs2OmNxRHlxtryRepNMgBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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