SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4506ccea62c3ca0cd66b60d5012703aa283d03051c361dd9e3bd73bc9f41985' 
  AND token = 'dsIQa1rD0j/ZUi7vW5aGuaVM+VhU5svKu9HlCeYDwpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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