SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26b929328c3ef866f3c3a643460588e09a21ad4a89c6dd1c7c526d5601d5ecd3' 
  AND token = 'TBnnujrkBT/gQTPSB8nE7YPmwvzLMfEOXnqVlC9rYFM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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