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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4693de70ba3080c8bd8cb7f58ddf55f7afc46f6b9dcab20ac82f82b7ac3f840' 
  AND token = 'gtqyWaFgkfTmMpEf6hH/WqQ+Iio4+B//th0td1SjON8=' 
  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"
    }
  }
}