SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b96075a6da979217fa1446868acd0cf75c78b0aa15b9572a6d9c70961abf384' 
  AND token = 'Anj/j0FFA8j0+/BK0PpxFKvWyx21sSHsGKmZJTAJl5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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