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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '15d1bfc8913b76c2bce6b8b9c9f3925d7dba5e9ba4c4068a37dfb2aaf1b90541' 
  AND token = 'quwsI6L3osMSnc5E+BnQHuQEU3hRyITL6oYfLSrc8no=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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