SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b790ca536a7d2e156f07d65ca2edd4e223da5f53e1fc941f7b57ed107a417dc' 
  AND token = 'A9U6uv5WDJbFt78bFZCqnGrIpUT9l+XicgE8fO+kR3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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