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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0ae5d1be2d3f5a57405b30383d98a35a1cd04fe8f40cc7c904140f8ea5fde394' 
  AND token = 'IT+Av7BJ6DjGHrNpT8GHXQXpfxx/z2sW3ba/6cmJNWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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