SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70193ad88bc8da81312172c0cc97b430eb9b4de5fbd0406358f42de1c9621de7' 
  AND token = '92PnqiTgth+/vpNL/HhucHul2/BVblc4VY0ZBLzsRh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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