SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4314da44b0cbc00c026d34e224da8abdafc6cde85c559bfebdf927dd8bf5a16c' 
  AND token = 'B14zsHcP4N8OnymbRqNoVlh/UMDqAV6nt58MYBFCilY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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