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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cf3dcb4c79720c00cee57f14dcd9778858385619b1b821a5f9322deb57cee1ee' 
  AND token = 'N7nbjkJsbQQ7r416Q1MF2WPJ9iicSGVBTfWVP+8VqLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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