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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '503e6711a183a0540cd9d709aee439bbcce53e28835258616bb959bb2529e0fb' 
  AND token = 'uFvBySdqCVuI9XwU54o+QNBHgbIX1SKOzesSNd/0mFM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}