SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2414253f9727f72e088979dfd20b3436bba3866b6c0ebea5156e4e620788a282' 
  AND token = '3yiFFbwbStEiuRkhxp1RunsAPvrllzzGXj991Nm465g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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