SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e01cd3d49bf2465fcdb9496d9cce04a8cc808df7e7ebebb5d53974f50475c548' 
  AND token = 'gniNw2cvuyT1csEsFE5NjMo4RfmErJhwt+QJqaE0wYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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