SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e29e2f29dd429a55c6073279d79c688b40e9c4a80bd0e1036c162010e79ca42' 
  AND token = 'ONIeBA9yegne0/9FM4aEs3l01ip3MaLd4kVICARoiYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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