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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cf345e38f1e1743e45147012846f693e3cb3cf60dc74846e4e6d4b8ee974dc93' 
  AND token = 'V1qn4QNqqXk+ZyEeZPGEODql9LwuMYl4G+iLo3Gjxqk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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