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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e3f1ae9e56aab103c9f8b01a8e30d54afd9b5d51dff4a31928761788a27f11d5' 
  AND token = '/rHTgCwc5H1m/F1AFFAZUuvrVMiqVs3cIE8wkReig88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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