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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df79b7378ba47dc7573f1fa2d212d97ab5a61fecd8c0a90bee0fa516ebe7a521' 
  AND token = 'ccODBZqGc4/UEzdjiVZ8zwgu2Ychz/9XDmXzxdZ1T8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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