SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd26f15319478384076ac35d7d9e8911045657a9d8fd48df2eaf36585f12b73b9' 
  AND token = 'trCq88sTKSkgZ+zVyomVQL678nW6izFeY2KwawBQEPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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