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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b243f41fae418a668d40024f73b6e5ab5ea1ee0c4caa9793cf27a57bb58ea3d5' 
  AND token = 'M3u8qCfmQeo1MwvlHbjKfISefT/wtFrJIKfo5RYK2do=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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