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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a819c4834023eb7a39caeba55b9efdcd32e32ca1b656b8ee9681411cd6d1b30' 
  AND token = 'MyHKhL4m/Z1Q4btc+MU4qgrI/IiCZOWDjNI7/jzPnuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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