SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b67498afa92a053b18cf410832fe5e2f04fda25b053764748111b9740d2c4175' 
  AND token = 'fw04bIz1iavhXdlEOIulPDU18m3xqvk0PtuTp86Bf5E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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