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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e46fb1ac48804191bafb9730305ffe64e3fbe790c5c50684f22ad890126f1e2a' 
  AND token = 'TWnGVRVddSdywREb2qK7zyuHX8tvxoiZ5he27NmiNiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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