SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a352d8aed4cd87f99ba9ce5aff43cf64e4154dd519b0065cadf4b03563cbbaf' 
  AND token = 'D7+k+ExQSs+qSCN6ACPPS0VNx3eDdLJTTe4sSoxAw98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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