SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf38975735ae8cc9fa58ab3002bd1d05db4465f119667ed452d439432f90c910' 
  AND token = '8dirw2w0La0HVR4Lo3ee+MjZLL32m+mJPLbkrx/ZqUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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