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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'eb22b253fb8a7f9db6bda7833d9fd717fe7cca3b786f338577b62e4cdc3b1ed1' 
  AND token = 't8jzLiFZZWPMmuoZeCd2ryjrwa2AXC6ti6lEzKHnmn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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