SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d256e12a9578eec987bfb7567ed5a3d82735bfabb29806e278aba2f2e91ae43' 
  AND token = 'uXeorha+2etDCmQj0oZPnfqazQIN058gntXsJdYABGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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