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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3eaea749bcd6e1b2d564ef285c7b614adc50ce535a89dc2d3eeeec5ea2daef6a' 
  AND token = 'edKOeHKtUFNAyGuIZoQlgjnOk8dgYSAOrSp8S9DeD3U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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