SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c994fef0a6975cd76f52122cdada1b415781dca5061efe45e0b32186d99ab9ef' 
  AND token = 'NjrnnGChXrq0LtirusZ8FheD6XvXqaOn8Oef36AvaCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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