SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4223f83e1617aa9e9699dfb7bfc4c40179798d32d49cdd3c129189f1a3f2f978' 
  AND token = 'n/zEzJ/kzspY+HQF7l7svfJCvdo8RwmB/3QOlaW/BQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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