SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93120e7c4af693c6361147e9fb0e2f8975570bf6ad9cdc440c3d41a847c0fae0' 
  AND token = '6dSerO+/fCCBIlt/mPcZqp76CixuDvDp1zGS/Q7fwBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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