SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b7456ee4a45cce240542a37fd31b8db68c59ea8462b0fc93356debc31fc3380' 
  AND token = 'PTukT9J5w/eOM0WDMH28bt2sT0S2XXal8Ry6/DLGKvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}