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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a95a4fc3eeef2aaf3813ce1dd2b88d3f8f9e1c75cf9dcccf9c46510d0b66db4f' 
  AND token = '3kQkQQaXsEOE+RokAFx4aLo8T12ais2+T2AZ0juAQ7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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