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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a16dfd4fb9c113ca4e79a703879ca15c9d6bb618f4e7151f0f8db2f54743761' 
  AND token = 'leeTqcKnQimD3mkCzgjIDY836+uukVzia96kyUMWigQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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