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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fc3f0015f224c10dea3a6b8a04f81e9dd621e73af367e77e988ad1c5ad1831d9' 
  AND token = 'oj9d3yN8YaAWE8SMAnRx1ndabBgUcvGJ806aWE+FFp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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