SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '556432dc304e970e343ac0677c78450b755dfc20da3fd8de696a58dca47d10e0' 
  AND token = 'Lcq+GBP6etAsweMm2iVyUsNB/+m1WgrRo+CHhictNac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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