SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b290f09bd98a05310a8151829a4e30f024ae43910b7c7540f032841058b13c28' 
  AND token = '7WaSY1hQw/+zDOZ0o7j2TKaGAtQfrvVm6xiLoZWLKvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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