SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ded8dfb0a36eedebbb821f094c005e15f43018661a5fac897a1d2dc0373d7f6' 
  AND token = 'RJBALKzREVsn/YJfpxvp2lTmI16I0F6QuC16XgQmnRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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