SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa34f956df7a59f019073f385a1febf86e588c2e3a96b54f61a7d8dc6852b05c' 
  AND token = '3j43YMNb/1TAByGyh0jQgQg+horixvXkZJooTWDKypg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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