SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03af165db05fe4f0c74426ae22e89665b21706b0969e6217cecaae5327c69a23' 
  AND token = 'xHuTksVMKl39JGrAvM98MTfLuvF7ECYc5ohBBTNefwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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