SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfcf71e7caa846a15a973b52b727cfe7241365e3bd6914310d66044ecc3eb4c8' 
  AND token = 'keIdSAvzw+1hHYlT6FFaJcsbN2DlILK1JQKvG0hLJ1w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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