SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5c9681219bcfdcf3dc719f5c044afa71894c17e15fc508fc7b025493c7a5898' 
  AND token = 'QgHdc6Q8IhLxQtsWrZkrwCJj83bmoZRbbnppDSpoiUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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