SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6575bd03b47a184846c66d0fa3fd8c1beed5f85da8b109d9f95cb4aebb9ef02e' 
  AND token = 'XSo/DdaWjrdo+LbmXwSGbXtQi91SA50LxL/akkFomoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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