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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '747d1112efe4d6c56e57f76807cad785e5c4bd9e8015b79edd16081e858a40cf' 
  AND token = 'rbjuMDMlgjFKxMAgkU/ckn+KL7kkFsoQbHLXYeCa+fw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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