SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71c13fc4a362cda5f50f6c1a2817c21e83e80bfb5c6189a705deea61784c8186' 
  AND token = 'ejsLfdPpeY5+DDZL5YY00APtgP82zFDRxNDJfu6Nhb8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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