SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53bf2a51e52de87ebf28f4a8ca8a0169398e1ce0a5166b47e5451915748f8d90' 
  AND token = 'JqrmQJj9ZAxLhlfS+N6UpeVwCggCFcKLgdoNQzpWSRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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