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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3b664cfc3389c57728c43ad92d7e13b48054d41f2baa87d4f6fa15cec53c3a6c' 
  AND token = 'gCcdMPDpsuzlw9Ca4cToD8z8pjXKBXZowizEY87pvwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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