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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ebc3ef8636d0ece4331e13f84d9952d2b68ea3cf6facd4ba28fe19b7dfc9aa1' 
  AND token = 'MBxlIycoJGudjDCwowANNOA0XQ/DJZnhJns92btNFPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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