SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f24c0015bd9061b3b47fa4295d3806c18268c2c82dcb6660789311df73803b9' 
  AND token = 'JDgVrGQe6bUhH/UNwN/E0Vgwmaj4oDZl/6j9m4uxQ/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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