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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7dfb158e15b5b4b8e6425c7e1ddb2abd48fb5383fa3c0bd47bc5011fee8e81c6' 
  AND token = 'sehcxVrhoqBuWHJqmOX8aezE3FZpdCZe2KQ9uCAMxrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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