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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e42ed0bd2203e3f2e31d14d4c04de6f8a4b3e47056bc030c9c55fddb09b2a6b6' 
  AND token = 'OKBcBEEvOj0iollMt/e8xfOrB/lX+s6CCOKVmZE6gQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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