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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2278c5083124e7dacc12908cdce3d8680e14a5f88829702a4565911c8c7c66f3' 
  AND token = 'eM76w3prsCUDLqp2meVrAjKOtHXMsFKlIfNZA6uabZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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