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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d1fd303670842cdb0f5c22ca7aea7d5f7df5c0f54186965fd0f8cfbdd50c284' 
  AND token = 'WqtUKWP0EkxxRreCOgdnCpl+F73j4sqvXW/QPg2PD7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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